Hillary Clinton and Donald Trump are sprinting across the country, doubling back to key battleground states that have become more competitive in the final two days of the presidential campaign.

Trump has new targets in his sights in historically Democratic states such as Michigan, New Mexico and Minnesota, where recent polls have shown some tightening.

On Sunday, the Republican nominee's campaign pointed to Clinton's scramble to shore up states like Michigan as a sign of momentum.

"Hillary Clinton is following us to Michigan, following us to Pennsylvania, following us to Wisconsin, following us to New Hampshire -- all these blue states on her schedule now for an arrogant campaign that's booked fireworks in New York to celebrate her victory on Tuesday night," Trump's campaign manager, Kellyanne Conway, said on CNN's "State of the Union." "She's got the president of the United States running around to blue states he carried twice to prop her up."

Once thought to be safe for Democrats, Michigan has become a last-minute battleground, with Clinton heading to Grand Rapids on Monday, the campaign announced this weekend. President Barack Obama, who won Michigan twice, will campaign in Ann Arbor on Monday. And former president Bill Clinton will make a stop in Lansing on Sunday.

But a top Clinton aide said Sunday that the race is effectively over and that the campaign believes Clinton will hold on to blue, upper Midwestern states such as Minnesota, Michigan and Wisconsin.

"We feel like we got a lead in Michigan," Clinton campaign chairman John Podesta said Sunday morning on NBC's "Meet the Press." He added, "We want to hold on to it, and we think we can do that."

"We think we have this race over. We're going to get over our 270 electoral votes," he added on ABC News' "This Week."

Trump will return to Northern Virginia on Sunday night as Republicans see new hope in a state where Clinton has long held a comfortable lead. And for the second time in less than 48 hours, Clinton will return to Ohio, which has consistently been one of Trump's strongest battlegrounds, to hold a rally with basketball star and Cleveland's hometown hero LeBron James.

Trump will campaign in Sterling Heights, Michigan, on Sunday evening. He will also make campaign stops in Iowa, Minnesota and Pennsylvania on Sunday.

"Donald Trump is closing, and he's got the momentum going into Tuesday," Republican National Committee Chairman Reince Priebus said on ABC News. "We believe a Pennsylvania, a Michigan, a Wisconsin could quickly move onto our board."

At a rally on Saturday night in Reno, Nevada, Trump was rushed offstage as security officials swarmed, but the candidate re-emerged after a few minutes and finished his speech. The U.S. Secret Service later said in a statement that it took action after "an unidentified individual shouted 'gun'" in front of the stage. Agents apprehended the person but found no gun, the statement said, adding that an investigation into the incident continues.

The man, who identified himself as Austyn Crites, 33, was released shortly after the incident, according to reports. He said he was holding a "Republicans against Trump" sign.

"When I pulled out the sign, people around me were trying to grab the sign," Crites told reporters, according to reports on the local Fox and NBC affiliate websites. "And so all that was occurring was booing, of course. That's what you would expect."

People from the surrounding crowd tackled him, Crites said. They started "kicking me and grabbing me in the crotch and just, just beating the crap out of me," he said.

Trump concluded his rally without further incident.

The GOP presidential nominee later released a statement thanking the Secret Service and local law enforcement for their "fast and professional response," adding that "nothing will stop us -- we will make America great again!"

In the aftermath of the event's disruption, Trump campaign aides and the candidate's son Donald Trump Jr. retweeted a supporter who credited Trump for returning to the stage after an "assassination attempt" and noted that Clinton had cut an event short earlier Saturday in Florida because of rain.

Meanwhile, a bus carrying reporters covering Democratic vice-presidential nominee Tim Kaine's stops in Florida was hit at high speed, according to reporters traveling with the senator. There were no reports of injuries. Kaine was several cars ahead of the bus, according to reporters in his motorcade.

In the closing days of the campaign, polling averages compiled by The Washington Post continue to show a close contest in several battleground states. In Michigan, Clinton holds just a two-point edge over Trump, 43 to 41 percent. She also holds a slim lead in New Hampshire (43 to 41 percent), which accounts for the renewed attention there in the closing days.

Clinton will rally in Manchester, New Hampshire, on Sunday with Khizr Khan. Khan is the father of fallen soldier Humayun Khan, whose challenge to Trump over the Republican's proposed ban on Muslim immigration was among the most memorable moments of the Democratic convention.

In Colorado, Clinton is up 43 percent to 41 percent. In Arizona, Trump leads by three points (46-43). Clinton is ahead by six points in New Mexico (40-34) and five points in North Carolina (48-43), Pennsylvania (47-42) and Wisconsin (45-40). She's up by four points in Virginia (45-41).

Trump holds a five-point lead in Ohio (46-41), where Clinton held a star-studded campaign rally on Friday night with rapper Jay-Z and Beyoncé, his wife.

The race remains ticktock tight in Nevada, where the candidates are tied at 44 percent each. In Florida, Clinton has a 47-to-46-percent advantage. Trump leads in Georgia (47-45), Iowa (46-41), and Utah (35-28), where third-party candidate Evan McMullin has been polling well.

Poll averages calculated by The Post for Clinton and Trump reflect recent polls that also include McMullin, Libertarian Gary Johnson and Green Party candidate Jill Stein where they are on the ballot and where results are available.